Corneal Ulcers in Cats: Recognising and Treating a Painful Eye Condition

Corneal ulcers are painful erosions of the eye's surface that occur commonly in cats, particularly following cat fights, herpesvirus infection, and in brachycephalic breeds. Prompt treatment prevents serious complications.

Key Facts

A corneal ulcer is a defect in the corneal epithelium (surface layer); ulcers are classified by depth — superficial, stromal, or descemetocoele (approaching perforation).
Common causes in cats include cat scratch injuries, feline herpesvirus-1 (FHV-1) ocular disease, chemical irritation, and eyelid abnormalities.
Persian and other brachycephalic cats are predisposed due to shallow orbits, reduced blink frequency, and exposure keratopathy from prominent eyes.
Indolent (chronic non-healing) ulcers in cats are often associated with FHV-1; the virus remains latent and reactivates during stress.
Clinical signs include squinting (blepharospasm), tearing, pawing at the eye, cloudiness of the cornea, and redness of the conjunctiva.
Diagnosis uses fluorescein dye staining — the dye adheres to the ulcerated area, staining it bright green under blue light.
Treatment depends on depth: superficial ulcers are treated with topical antibiotics and analgesia; deep or infected ulcers may require surgical intervention.
Descemetocoele (very deep ulcers where only Descemet's membrane remains) are ocular emergencies requiring immediate specialist referral.

Welfare Considerations

Corneal ulcers cause significant acute pain: the cornea is one of the most densely innervated tissues in the body, and even superficial defects cause intense discomfort. Cats with corneal ulcers blink constantly, hold the eye closed, and may be reluctant to expose the eye to light. The chronic blepharospasm (squinting) itself causes periocular muscle fatigue and discomfort. Owners who delay seeking treatment — attributing squinting to "just a scratch that will heal" — inadvertently prolong significant suffering. Adequate analgesia (topical NSAIDs where appropriate, systemic buprenorphine in severe cases) is an essential welfare component of treatment, not an optional addition. Brachycephalic cats with recurrent ulcers may benefit from referral to a veterinary ophthalmologist for corrective surgery addressing the underlying anatomical predisposition.

What You Can Do

Seek veterinary attention within 24 hours if your cat shows any eye squinting, tearing, or cloudiness — corneal ulcers worsen rapidly without treatment.
Prevent your cat from rubbing their eye — an Elizabethan collar (e-collar) during treatment is essential to prevent self-trauma.
Apply all topical eye medications as prescribed — treatment frequency (often every 4-6 hours) is critical for healing deep ulcers.
Return for recheck examinations — corneal ulcers can change rapidly, and progress must be confirmed by fluorescein staining.
If you have a brachycephalic cat with recurrent eye problems, discuss referral to a veterinary ophthalmologist to assess for correctable anatomical causes.